Heat sink with thermally conductive cover

ABSTRACT

A heat sink includes a base, two heat pipes, a fin assembly, and two thermally conductive cover. The heat pipes are thermally connected to the base. Each of the heat pipes includes a cylindrical body and an ineffective end portion distal from the base. The ineffective end portion is connected to the cylindrical body. A diameter of the ineffective end portion is smaller than that of the body. The fin assembly is thermally coupled to the two heat pipes. Each of the thermally conductive covers envelops the ineffective end portion and is in thermal contact with the ineffective end portion and the fin assembly.

BACKGROUND

1. Technical Field

The present disclosure relates to heat sinks with thermally conductive covers.

2. Description of Related Art

Heat sinks include a heat pipe and a fin assembly coupled to the heat pipe. A metal sheet is typically cut to size and then rolled up to form the cylindrical body of the heat pipe. A distal cut end of the metal sheet is crimped and soldered. However, the soldered distal end portion (also called an ineffective end portion) is unable to dissipate heat using heat pipe principle. Thus, when the heat pipe is mounted to the fin assembly, the soldered distal end extends from the fin assembly. This reduces a usage ratio and a heat-dissipation efficiency of the heat sink.

Therefore, a heat sink, which can overcome the above-mentioned problems, is needed.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of a heat sink, according to a first embodiment.

FIG. 2 is a partially exploded view of the heat sink of FIG. 1.

FIG. 3 is a sectional view taken along line III-III of the heat sink of FIG. 1.

FIG. 4 is a sectional view of a heat sink, according to a second embodiment.

DETAILED DESCRIPTION

Referring to FIGS. 1 to 3, a heat sink 100, according to a first embodiment, includes a base 10, two heat pipes 20, a fin assembly 30, two thermally conductive covers 40, and a number of fasteners 50. Material of the base 10, the fin assembly 30, and the thermally conductive covers 40 may be copper or aluminum.

The base 10 is substantially cuboid and defines four base through holes 101 at four corners thereof. The base 10 includes a first surface 102 and an opposing second surface 103. The base through holes 101 extend through the first surface 102 and the second surface 103. The first surface 102 may be in thermal contact with a heat source (not shown). Two grooves 104 are defined in the second surface 103. The two grooves 104 are substantially parallel to each other.

Each of the heat pipes 20 is substantially U-shaped. The heat pipes 20 are connected to the base 10 on the second surface 103. Each pipe 20 includes a body 201 and an ineffective end portion 202 connected to the body 201. The body 201 is a cylinder and extends through the fin assembly 30 and is in thermal contact with the fin assembly 30. The body 201 dissipates heat according to heat pipe principles. A diameter of the ineffective end portion 202 is smaller than that of the body 201. Material of the body 201 and the ineffective end portion 202 may be copper or aluminum.

In this embodiment, the body 201 is substantially U-shaped. An end of the body 201 distal from the base 10 and the ineffective end portion 202 are two distal ends of the heat pipe 20. A horizontal portion of each body 201 is received in the corresponding groove 104 and is in thermal contact with the base 10 on the second surface 103. A vertical portion of each body 201 extends through the fin assembly 30 and is in thermal contact with the fin assembly 30.

The fin assembly 30 is coupled to the heat pipe 20 and includes a number of fins 301 and four supports 60. The fins 301 are parallel to each other. The supports 60 are connected to four corners of the each fin 301, respectively. The supports 60 are positioned on the base 10 adjacent to the base through holes 101, respectively. Material of the support 60 may be copper or aluminum. Thus, the supports 60 can also act as heat dissipation members. Paths and areas of heat dissipation increase.

Each of the fins 301 defines four through holes 302 to allow the two U-shaped heat pipes 20 to extend therethrough. In this embodiment, a diameter of the through hole 302 for the ineffective end portion 202 to extend through (hereinafter a cover through hole 303) is greater than that of the through hole 302 for the body 201 to extend through. The cover through hole 303 is defined in the two top fins 301 distal from the base 10. A diameter of the ineffective end portion 202 is smaller than that of the through hole 302 and the cover through hole 303.

The thermally conductive cover 40 extends through the cover through hole 303 to envelop the ineffective end portion 202. The thermally conductive cover 40 is in thermal contact with the ineffective end portion 202 and the two top fins 301. In this embodiment, the thermally conductive cover 40 is substantially a hollow cylinder. A circular inner side surface 41 of the thermally conductive cover 40 is spaced from the ineffective end portion 202 and an end face of the ineffective end portion 202 is in contact with the cover 40. Thus, the heat can be transferred from the ineffective end portion 202 to the fins 301 through the thermally conductive cover 40 and heat-dissipation efficiency of the heat sink 100 increases.

Each of the fasteners 50 is configured for securing the heat sink 100 to the heat source. In this embodiment, the fastener 50 includes a bolt 501 and a compression spring 502. The bolt 501 extends though the compression spring 502 and the base through holes 101. Each compression spring 502 is compressed between the base 10 and a cap of the corresponding bolt 501. Thus, inclination of the heat sink 100 relative to the heat source can be adjusted upon elasticity of the compression spring 502.

Since the covers 40 of mass production will have a uniform diameter, when manufacturing the heat sink 100, the cover through holes 303 can be defined with a uniform diameter whatever the diameter of the ineffective end portion 202 is. This simplifies the manufacturing of the heat sink 100.

Referring to FIG. 4, a heat sink 200, according to a second embodiment, is shown. The difference between the heat sink 200 of this embodiment and the heat sink 100 of the first embodiment is that thermally conductive covers 80 of the heat sink 200 are different.

In this embodiment, each of the thermally conductive covers 80 is in thermal contact with an outer circumferential surface 81 of an ineffective end portion 602 of a heat pipe 600. Thus, contact area between the ineffective end portion 602 and the thermally conductive cover 80 increases and heat dissipation efficiency of the heat sink 200 also increases.

It is to be understood, however, that even though numerous characteristics and advantages of the present embodiments have been set forth in the foregoing description, together with details of the structures and functions of the embodiments, the disclosure is illustrative only, and changes may be made in detail, especially in matters of shape, size, and arrangement of parts within the principles of the disclosure to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed. 

1. A heat sink, comprising: a base; at least one heat pipe thermally connected to the base, the at least one heat pipe comprising a cylindrical body and an ineffective end portion distal from the base, the ineffective end portion connected to the cylindrical body, a diameter of the ineffective end portion being smaller than that of the body; a fin assembly thermally coupled to the at least one heat pipe; and at least one thermally conductive cover enveloping the ineffective end portion and in thermal contact with the ineffective end portion and the fin assembly.
 2. The heat sink of claim 1, wherein the fin assembly comprises a plurality of parallel fin, the fins defining a plurality of through holes for extension of the at least one heat pipe therethrough.
 3. The heat sink of claim 1, wherein the at least one heat pipe comprises two heat pipes, each of the heat pipes being U-shaped.
 4. The heat sink of claim 3, wherein the base comprises a first surface and an opposing second surface, the first surface configured for being in thermal contact with a heat source, two grooves being defined in the second surface and each configured for receiving the corresponding heat pipe.
 5. The heat sink of claim 1, further comprising a plurality of fasteners configured for securing the base.
 6. The heat sink of claim 5, wherein each of the fasteners comprises a bolt and a compression spring, the base defining a plurality of base through holes, the bolt extending through the compression spring and the base through hole, each compression spring compressed between the base and a cap of the corresponding bolt.
 7. The heat sink of claim 2, further comprising a plurality of supports each connected to a corresponding corner of the fin and the base.
 8. The heat sink of claim 1, wherein the thermally conductive cover is in thermal contact with an end face of the ineffective end portion.
 9. The heat sink of claim 1, wherein the thermally conductive cover is in thermal contact with an outer circumferential surface of the ineffective end portion. 